The invention relates to improvements in dryer drums, and more particularly to an improved paper machine dryer drum with a condensate removal adapted and constructed for accurate adjustment for improved condensate removal from the drum.
Such dryer drums are heated by live steam directed into the interior and a continuous web of paper is threaded in serpentine fashion over a series of dryer drums. As the heat energy from the steam within the dryer drum transfers as heat through the shell of the hollow cylindrical drum to the paper web, condensate is formed within the drum. This condensate tends to collect on the inner cylinder surface of the drum or to "rim" as the drum rotates, and the condensate is removed by a condensate removal syphon tube. Because the condensate provides an insulation effect, the layer of condensate must be maintained at minimum thickness for the most effective heat transfer. The effective removal of the condensate is directly related to the spacing between the inner end of the syphon tube and the inner surface of the drum.
In devices heretofore available, different arrangements were employed for adjusting the spacing between the inner end of the syphon tube and the drum. This creates difficulties because with heat expansion and contraction of the drum, the spacing can change, and it is desirable that the adjustment can be accomplished during operation inasmuch as it would be completely impractical to have to shut down the operation of the paper machine for this adjustment. One arrangement for adjusting the end of the condensate tube relative to the drum surface is shown in U.S. Pat. No. 1,953,525 wherein it is necessary to provide a flexible condensate syphon tube which can pivot within the drum. Structures of the type shown in this patent encounter disadvantages in that there is an instability in having to provide a flexible tube, and mechanism and equipment is required which operates inside of the dryer drum and is subject to vibration, going out of adjustment, and inaccessibility for repair and observation.
Accordingly, an object of the present invention is to provide an improved dryer drum and syphon for condensate removal which is of an improved simplified construction and which is more reliable in operation.
A further object of the invention is to provide an improved adjustment mechanism for the syphon tube of a steam dryer drum where it provides a minute and accurate control of the position of the inner end of the tube relative to the drum wall and which adjustment can be effected at anytime during operation of the drum.
A still further object of the invention is to provide an improved adjustment mechanism for locating the inner end of the condensate syphon tube of a steam drum relative to the inner wall of the drum which makes possible minute adjustment and wherein the operating portions are outside of the dryer drum where they can be easily reached and serviced.
Other objects, advantages and features will become apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the specification, claims and drawings, in which: